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Fascicular Ventricular Arrhythmias

Various types of ventricular tachycardia (VT) are known to arise from the His-Purkinje network in patients with or without structural heart disease (SHD). This chapter describes the clinical manifestation, mechanism, diagnosis, and therapeutic options in each VT. We first focus on the basic concept of the most common reentrant fascicular VT, which is known as verapamil-sensitive fascicular VT. Recent findings on the VT circuit and characteristics…

Premature Ventricular Contraction Ablation With Anatomic Guidance: Papillary Muscles, Moderator Band, and Valve Annulus Sites

Introduction Most ventricular arrhythmias (VAs) in patients without structural heart disease originate from the outflow tracts of the right ventricle (RV) and left ventricle (LV). However, up to 20% of idiopathic VAs may originate from non–outflow tract sites, including the tricuspid and mitral valve (MV) annuli, para-Hisian region, cardiac crux, moderator band (MB), and papillary muscles in the RV and LV. Mapping and ablation of idiopathic…

Outflow Tract Ventricular Tachyarrhythmias: Mechanisms, Clinical Features, and Management

Idiopathic ventricular tachycardias (VTs) typically occur in the absence of structural heart disease and can originate from multiple anatomic regions, including the left ventricular outflow tract (LVOT) and right ventricular outflow tract (RVOT), the left fascicular system, the mitral and tricuspid annuli, and the papillary muscles, or they can develop in the perivascular epicardial space. More than half of all idiopathic VTs originate from the outflow…

Premature Ventricular Complexes

Epidemiology History Irregularities in pulse and their association with poor outcomes have been recognized for centuries. The Chinese physician Pien Ts’Io, who lived around 6 bce , taught that occasional pulse irregularities did not predict an adverse outcome; however, frequent irregularities (1 in 10 beats) were linked with an ominous prognosis (often resulting in death within a year). Reliable differentiation of PVCs from other arrhythmias became…

Sudden Cardiac Death in Adults

Sudden cardiac death (SCD) is defined as death after a sudden cardiac arrest (SCA) in a patient with either known or previously undetected cardiac abnormalities in whom the mode and time of death are unexpected. Transient endogenous influences on cardiac physiology, such as electrolyte, metabolic, or respiratory disturbances, or exogenous factors, such as drug effects or chest wall trauma (as in commotio cordis ), contribute to…

Typical and Atypical Atrial Flutter: Mapping and Ablation

Atrial flutter (AFL) is one of the most common cardiac arrhythmias in humans, afflicting approximately 0.19 million people in the United States in 2005; its prevalence is expected to increase to 0.44 million by 2050 because of the aging population. AFL often occurs in the context of structural heart disease (e.g., valvular, ischemic heart disease, cardiomyopathy) and may manifest during acute disease process (e.g., sepsis, myocardial…

Left Atrial Appendage Management: Anatomy, Physiology, and Role in Atrial Fibrillation–Related Stroke

Acknowledgment C.R.E. discloses significant research funding (to Vanderbilt University) from Medtronic Inc., Boston Scientific Inc., and Boehringer Ingelheim Inc. He is on the advisory board/consultant for Medtronic Inc., Boston Scientific Inc., AtriCure, Inc., and Abbott Medical Inc. A.N.K. is a speaker for Janssen Pharmaceuticals and Zoll. Left Atrial Appendage Anatomy And Imaging The left atrial appendage (LAA) is formed from the left wall of the primary…

Ablation for Atrial Fibrillation

Background Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with an estimated prevalence of 2% among unselected adults, an increasing prevalence with each decade of life, and a twofold higher risk in men relative to women. , The three most common symptoms directly attributed to AF are impaired exercise tolerance caused by an inappropriate heart rate response during exertion, palpitations caused by an irregular…

Atrial Fibrillation: Mechanisms, Clinical Features, and Management

Atrial fibrillation (AF) is responsible for significant impairment in quality of life and thromboembolism and contributes to substantial morbidity and health care expenditure. AF is the most common arrhythmia in humans. It is heterogeneous in its mechanism, presentation, and clinical course, and therefore patients require individualized treatment. This chapter discusses the epidemiology, nomenclature, current mechanistic insights, and contemporary treatment strategies for the management of AF. Epidemiology…

Preexcitation, Atrioventricular Reentry, Variants

The cardiac electrical impulse normally travels from the atria to the ventricles via the atrioventricular (AV) node, His bundle, bundle branches, and Purkinje fibers. Preexcitation refers to electrical activation of the ventricles via an accessory pathway (AP), occurring earlier than expected via the normal AV conduction system. APs consist of myocardial tissue that bypasses all or part of the normal AV conduction system. These pathways probably…

Junctional Tachycardia

Junctional tachycardia, alternatively known as junctional ectopic tachycardia (JET), originates from the atrioventricular (AV) junction, which encompasses the AV node and His bundle. JET is rarely encountered, especially in the adult population, and its pathogenesis remains incompletely understood. Furthermore, its presentation can be variable, and the diagnosis and therapy can be challenging. This chapter focuses on the tachycardic forms of junctional arrhythmia, although escape rhythms that…

Atrioventricular Nodal Reentrant Tachycardia

Atrioventricular (AV) nodal reentrant tachycardia (AVNRT) was originally proposed to result from reentry confined within the compact AV node. Now, however, AVNRT is thought to involve the AV node, at least two atrionodal connections, and a component of the atrial and/or coronary sinus (CS) myocardium. Much of our current understanding about the components of the reentrant circuits has evolved from the development of ablation procedures in…

Atrial Tachycardia

Introduction Atrial tachycardia (AT) is an important entity in the differential diagnosis of narrow complex tachycardia. It is defined as an arrhythmia that originates in atrial tissue that does not encompass the sinus node. Although nonsustained asymptomatic episodes are frequently seen in routine Holter recordings, the prevalence of this arrhythmia is approximately 5% to 15% in patients referred for routine invasive electrophysiologic evaluation. Definition ATs are…

Supraventricular Tachycardias: Diagnostic Maneuvers in the Electrophysiology Laboratory

Introduction Paroxysmal supraventricular tachycardia (PSVT; Table 70.1 ) refers to a group of heterogenous arrhythmias with different electrophysiologic mechanisms manifesting as a regular narrow complex tachycardia, typically having an abrupt onset and offset. The differential diagnosis for these disorders includes atrioventricular nodal reentrant tachycardia (AVNRT; see Chapter 72 ), atrioventricular reentrant tachycardia (AVRT; see Chapter 74 ), atrial tachycardia (AT; see Chapter 71 ), and junctional…

Genetic Testing

Major advances have been made over the last 3 decades that have defined the genetic basis of many medical diseases. There are now more than 40 different cardiovascular diseases directly caused by variants in genes that encode cardiac proteins. These cardiovascular diseases include inherited cardiomyopathies, inherited arrhythmia syndromes, metabolic disorders, familial aortopathies, and congenital heart diseases. Identification of the genetic causes of cardiovascular disease allows early…

Noninvasive Electrocardiographic Imaging of Arrhythmogenic Substrates and Ventricular Arrhythmias

Acknowledgments This chapter is dedicated to Professor Bruno Taccardi—a scientist, a gentleman, and a dear friend. He will be greatly missed. I am indebted to my outstanding graduate students, research and clinical fellows, and many collaborators who helped make ECGI a reality of great research and clinical promise. Studies presented in this chapter were supported by grants R01-HL33343 and R01-HL49054 from the National Institutes of Health–National…

Autonomic Nervous System Assessment for Syncope and Arrhythmia Risk

Acknowledgment Dr. Benditt is supported in part by a grant provided by the Dr. Earl E. Bakken family in support of heart-brain research. Introduction The autonomic nervous system (ANS) controls multiple critical involuntary “background” functions in virtually all body organs. Some of these activities are controlled by central centers, whereas in other cases (e.g., gastrointestinal motility) there is substantial local autonomy. In any case, if moment-to-moment…

Intracardiac Echocardiography for Electrophysiology

The rapid growth in the complexity of interventional electrophysiology made the inherent limitation of fluoroscopic imaging quite clear. Although three-dimensional (3D) electroanatomic mapping and preprocedural anatomic imaging have been important in augmenting our intraprocedural understanding of cardiac and extracardiac anatomy, these modalities are potentially limited by their artificially static nature and in difficulties with adequate registration. Intracardiac echocardiography (ICE) provides real-time imaging of cardiac and extracardiac…

Magnetic Resonance Imaging for Electrophysiology

Introduction Today’s successful electrophysiologist must not only be a competent proceduralist but also a physician who understands the pathophysiology of arrhythmias, new drug targets and developments, complexities of new technologies, and various treatment options. Additionally, an in-depth understanding of cardiac anatomy, common anatomic variations, typical scar patterns with each pathology, and how anatomic arrhythmia substrates relate to diagnostic and procedural nuances is increasingly important. Advanced imaging…

Computed Tomography for Electrophysiology

This chapter reviews the technical background and current uses of cardiac computed tomography in the diagnosis and management of atrial and ventricular arrhythmias. Imaging plays a fundamental role in the diagnosis and treatment of cardiac arrhythmias. The increased use of imaging has led to an improved ability to understand and successfully treat complex tachycardia circuits. Traditional imaging methods used in the electrophysiology laboratory such as x-ray…